0

200

400

600

800

1000

1200

Obs. 2015 Obs. 2016 CH4/CO (2015)* CO

EDGAR2010

CH4/CO2(2016) * CO2

NEI2014

US GHGI 2012Maasakkers et

al. [2016]

EDGAR v4.3.22012

StateInventory 2014

in Balt-Wash

CH4

Emiss

ions

(mol

s-1)

MD

DC

VA

-79 -78 -77 -76 -75

38

38.5

39

39.5

40

40.5

Longitude ()

La

titu

de

()

[O3] (ppbv)

0

10

20

30

40

50

60

70

80

90

100

Air Quality Flight in Maryland on 8 Sept. 2016Traditional westerly/easterly flight pattern

-74.5 -74 -73.5 -73

40.4

40.6

40.8

41

41.2

41.4

41.6

Longitude ()

La

titu

de

()

[O3] (ppbv)

40

60

80

100

120

140

Aircraft Measurements of Air Pollutants and Greenhouse Gases in the Mid-Atlantic StatesXinrong Ren1,2,*, Doyeon Ahn1, Phil Stratton1, Sarah Benish1, Hao He1, Ross Salawitch1, and Russ Dickerson1

1University of Maryland College Park; 2NOAA Air Resources Lab; *Contact: Xinrong.ren@noaa.gov

Motivation• Mid-Atlantic states occasionally experience severe air smog in summer.

• Urban greenhouse gas (GHG) emissions contribute to the majority (~70%) of the anthropogenic GHG emissions.

• Quantification of urban greenhouse gas (GHG) emissions is important for establishing scientifically sound and cost-effective policies for mitigating GHGs.

Summary and Future Work

▪ Aircraft mass balance approach is a valuable tool for estimating urban GHG emission.

▪ CO & CO2 emissions: obs. agree with emission models in general. The discrepancies may be explained by uncertainties in mass balance approach and emission models.

▪ The EDGAR Inventory may underestimate CH4 emissions by a factor of 2-3.

Future work

▪ More flights will be conducted over Mid-Atlantic and NYC in the future to reduce uncertainties

▪ Biosphere CO2 uptake/emissions and inversion modeling

▪ NO2 (& NOy) emissions and compare to GEO-TASO and satellites

CH4 and CO2 during the flight on May 18, 2017

• High correlated between observed CO2 and CH4.

• Unlikly the same sources for CO2 & CH4, but likelythe sources are collocated.

We could use observed ratios to evaluate emission models.

Gridded CO & NOx emissions in EDGAR v4.3.2 for 2012

EDGAR v4.3.2CO emissions

NYC urban center: 302 mol/s (481 mol/s)

Metropolitan NYC: 511 mol/s (630 mol/s)

NYC urban center: 116 mol/s

Metropolitan NYC: 168 mol/s

EDGAR v4.3.2NOx emissions

Obs

-75 -74.5 -74 -73.5 -73 -72.5

39.8

40

40.2

40.4

40.6

40.8

41

41.2

41.4

41.6

41.8

Longitude ()

Latitu

de ()

CO Emissions in 2012 (kg/s)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-75 -74.5 -74 -73.5 -73 -72.5

39.8

40

40.2

40.4

40.6

40.8

41

41.2

41.4

41.6

41.8

Longitude ()

Latitu

de ()

NOx Emissions in 2012 (kg/s)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-75 -74.5 -74 -73.5 -73 -72.5

39.8

40

40.2

40.4

40.6

40.8

41

41.2

41.4

41.6

41.8

Longitude ()

Latitu

de ()

CH4 Emissions in 2012 (kg/s)

0.1

0.2

0.3

0.4

0.5

0.6

-75 -74.5 -74 -73.5 -73 -72.5 -72

39.8

40

40.2

40.4

40.6

40.8

41

41.2

41.4

41.6

41.8

Longitude ()

Latitu

de ()

CH4 Emissions in 2012 (kg/s)

0.1

0.2

0.3

0.4

0.5

0.6

Gridded CH4 Emissions in EDGAR and Maasakkers InventoryEDGAR v4.3.2 for 2012 Maasakkers for 2012

EDGAR v4.3.2CH4 emissions

NYC urban center: 200 mol/s (418 mol/s)

Metropolitan NYC: 285 mol/s (630 mol/s)

NYC urban center: 130 mol/s (418 mol/s)

Metropolitan NYC: 251 mol/s (630 mol/s)

Maasakkers CH4 emissions

Obs Obs

Comparison with CO2 emission models(Close up NYC Metropolitan Area — corresponding to the flight on May 18, 2017)

Obs

CTBio

Obs.

Fossil-Fuel CO2 emission models:

➢ ACES (1 km, v1)July 2014

➢ ODIAC (1 km, v2017)July 2016

➢ FFDAS (0.1°, v2.0)July 2015

➢ EDGAR (0.1°, v4.3.2)July 2012

➢ CarbonTracker (1°, CT2017) July 2016

CTBio

Comparison with CO2 Emission Models(NYC urban center — corresponding to the flight on July 2, 2018)

Emission Rates (E. R.) based on Mass Balance

Transect # CO2 E. R.(mol/s)

CH4 E. R.(mol/s)

CO E. R.(mol/s)

NO2 E. R.(mol/s)

1 75,300 222 488 --

2 62,300 260 397 24.3

3 65,700 523 567 28.4

4 85,110 668 489 21.9

Mean 74,700 418 481 24.9

July 2, 2018 (NYC urban center)

May 18, 2017 (the Greater NYC Metro.)

Transect # CO2 E. R.(mol/s)

CH4 E. R.(mol/s)

CO E. R.(mol/s)

NO2 E. R.(mol/s)

1 101,000 560 642 10.4

2 127,000 700 628 7.6

Mean 114,000 630 636 9.0

High [CO2] & [CH4] observed over the Sound and CT/RI coastal areas were associated with airflow passing NYC/NJ

Mass Balance Approach

E. R. : emission rate (flux)[C] : concentrations (downwind)[C]b : concentration in background U⊥ : perpendicular wind speed

38.2 38.4 38.6 38.8 39 39.2 39.4409

410

411

412

413

414

415

416

417

[CO

2] (p

pb

v)

Latitude ()

2500ft

1000 ft

DCplume

Baltimoreplume

Morgantown

Chalk Point

Brandon Shores

Background

BackgroundCO2, CH4, CO

UrbanΔCO2, ΔCH4, ΔCO

∆x

∆z

Obs. winds

CO2 on track

12h HYSPLITback trajectories NYC urban center

Metro. NYC

>420 7 m/s7 m/s

21 21.5 22 22.50

500

1000

1500

2000

Alt AGL (m)

Track Angle ()*5

21 21.5 22 22.5400

410

420

430

440

[CO

2]

(ppm

)

21 21.5 22 22.51900

2000

2100

2200

[CH

4]

(ppb)

21 21.5 22 22.5

100

200

300

400

500

[CO

] (p

pb)

21 21.5 22 22.50

5

10

[NO

2]

(ppb)

Hour (UTC)

Time series of Alt, Ozone, CO2, CH4, and CO

Transect #1 #2#3 #4

Afternoon Flight on July 2, 2018

Wind

-74.5 -74 -73.5 -73

40.2

40.4

40.6

40.8

41

41.2

41.4

Longitude ()

La

titu

de

()

[CH4] (ppbv)

1900

1950

2000

2050

2100

2150>2150

A Typical Air Quality & Mass Balance FlightAfternoon Flight (~2:30-5:30 PM) on 7/2/2018

Wind

Transect #1

#2#3

#4

• Ozone and CH4 plume downwind of NYC.

GPS Position (Lat, Long, Altitude)

Met (T, RH, P, wind speed/direction)

Trace gases:

O3: UV Absorption, modified TECO

SO2: Pulsed Fluorescence, modified TECO

CH4/CO2/CO/H2O: Cavity Ringdown, Picarro

NO2: Cavity Ring Down, Los Gatos

NO: Chemiluminescence, modified TECO

VOCs: grab canisters/GC-FID

Aerosol Optical Properties:

Scattering: bscat (@450, 550, 700 nm), Nephelometer

Absorption: bap (565 nm), PSAP

Black Carbon: Aethalometer

Aerosol Inlet

Gas Inlet

Met Sensors

Measurements

Results

Acknowledgments

Correlation among CO, CO2 and CH4

380 390 400 410 420 430 440 450 460 470 4800

50

100

150

200

250

300

350

400

450

[CO2] (ppmv)

[CO

] (

ppbv)

y = 4.2742x - 1603.1459

r2 = 0.80827

50 100 150 200 250 300 350 400 4501850

1900

1950

2000

2050

2100

2150

2200

2250

[CO] (ppbv)

[CH

4]

(ppbv)

y = 1.0614x + 1777.264

r2 = 0.86

Afternoon Flight on May 18, 2017

380 390 400 410 420 430 440 450 460 470 4801700

1800

1900

2000

2100

2200

2300

[CO2] (ppmv)

[CH

4]

(ppbv)

y = 5.181x - 192.916

r2 = 0.92

EDGAR v.4.3.2 for 2012𝐶𝑂 𝐸. 𝑅

𝐶𝑂2 𝐸. 𝑅= 𝟒. 𝟒𝟖 ppb CO/ppmCO2

Observed Δ[𝐶𝑂]

Δ[𝐶𝑂2]

= 4.27 ppb CO/ppmCO2

EDGAR v.4.3.2 for 2012𝐶𝐻4 𝐸. 𝑅

𝐶𝑂2 𝐸. 𝑅= 𝟏. 𝟕𝟎 ppbCH4/ppmCO2

Observed Δ[𝐶𝐻

4]

Δ[𝐶𝑂2]

= 5.18 ppb CH4/ppmCO2

EDGAR v.4.3.2 for 2012

𝐶𝐻4 𝐸. 𝑅

𝐶𝑂 𝐸. 𝑅= 𝟎. 𝟑𝟖 ppbCH4/ppbCO

Observed Δ[𝐶𝐻

4]

Δ[𝐶𝑂]= 1.06 ppb CH4/ppmCO

y = 4.27x – 1603r2 = 0.81

y = 5.18x – 192r2 = 0.92

y = 1.06x + 1777r2 = 0.86

• EDGAR CH4 emissions may be significantly underestimated for the NYC area.

• EDGAR CO and CO2 emissions may be good.

Emission Rates (E. R.) based on Mass Balance

CO2 Emissions from Washington, DC/Baltimore CH4 Emissions from Washington, DC/Baltimore

BaltimoreNew York City

138.75 138.8 138.85 138.9

1900

1950

2000

2050

2100

2150

2200

Day of year (days)

CH4 (ppbv)

CO4 ppm*5

380 390 400 410 420 430 440 450 460 470 4801700

1800

1900

2000

2100

2200

2300

[CO2] (ppmv)

[CH

4]

(ppbv)

y = 5.3042x - 244.8424

r2 = 0.94584